ET’s Keltie Knight spoke with the Oscar-nominated actor at the L.A. premiere of his new movie, Beautiful Boy, where he discussed what it was like when Brad Pitt, one of the film’s producers, showed up on set.

“It was nuts, yeah, you could feel the star power in the room and seriously it felt like an energy had shifted in the room before I saw he was there,” he explained. “It's a real thing that just humanized all of us.”

In the film, Chalamet plays Nic, a young man battling his addiction to meth with the help of his father, David (Steve Carell). On the red carpet, the 22-year-old actor explained how he approached such a difficult and challenging role.

“It felt like, to try and play a drug addict would be, like, self-serving or something but to play a human who is addicted… that felt like where I could find my through line and I hope it works for people or audiences if they see it and hopefully they do. But more importantly, it's like, I hope it's a representation of what people are going through in the world but also in America today.”